<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    #d1{
      border: 1px solid red;
      width: 200px;
      height: 200px;
      margin-left: 50px;
      margin-top: 50px;
      margin-right: 50px;
      margin-bottom: 50px;
      margin: 50px;
      margin: 100px 100px;
      margin: 50px 100px 50px 100px;
    }
    #d2{
     border-left: 1px solid red;
      border-right: 1px solid red;
      border-top: 1px solid red;
      border-bottom: 1px solid red;
      border: 2px solid red;
      border-radius: 50px;
    }
    #d3{
      margin-top: 30px;
      width: 150px;
      height: 150px;
      border: 1px  solid red;
      padding-top: 50px;
      padding-left: 50px;
    }
  </style>
</head>
<body>
<div id="d1">测试外边距</div>
<div id="d2">测试边框</div>
<div id="d3">测试内边距</div>
</body>
</html>